In the prior art, coil-based metal detectors are known for detecting such a hidden object. Such detectors generate a magnetic field within an area to be measured. If there is a metallic object in the area to be measured, the object is detected due to its influence on the magnetic field generated. Frequently, at least two receiving coils are used for determining the magnetic field generated which are oriented and connected to one another in such a manner that in the absence of a metallic object in the area to be measured, the measurement signal supplied jointly by both receiving coils tends toward zero (differential measurement). In one variant, a number of transmitting coils are used for generating the magnetic field which are driven in such a manner that the signal measured in the two receiving coils goes to zero independently of a presence of a metallic object in the area to be measured (field-compensated measurement).
DE 10 2007 053 881 A1 describes a measuring method for determining the position or the angle of a coil with respect to two other coils. For this purpose, an alternating magnetic field is generated by means of two transmitting coils arranged at an angle to one another. A receiving coil is brought into the alternating magnetic field and the drive to the transmitting coils is changed in such a manner that the same voltage is induced in the receiving coil by each of the transmitting coils. A ratio of current values supplied to the transmitting coils is used as a measure for a determination of the position and/or angle of the receiving coil with respect to the transmitting coils.
DE 10 2004 047 189 A1 discloses a metal detector having printed coils.
The disclosure is based on the object of providing a simple and accurate detector for a metallic object. A further object of the disclosure consists in specifying a method for determining the metallic object.